1. Field of the Invention
The present invention relates to a reservoir cap for use in a braking system, clutch system or the like, more particularly to a reservoir cap having a sealing member suitable to fluid-tightly cap the openings of reservoirs for various liquid operated machines.
2. Description of the Prior Art
In Japanese Utility Model Laid-open Publication No. 58-158746, there is disclosed a cap assembly which closes an opening of a reservoir for storing a braking fluid, and which is provided with an annular sealing member having a circular cross section.
According to the above-described prior art, however, in order to provide an effective seal between the cap assembly and the reservoir, it is necessary to enlarge the diameter of the sealing member for example, to thereby strengthen a pressing force between the sealing member and the reservoir, i.e., enlarge an interference therebetween, since the annular sealing member has the circular cross section. Consequently, when the cap assembly is disposed on the reservoir, the sliding resistance between the sealing member and the reservoir increases to impair a fitting ability of the cap assembly.